Effects of climate warming on net primary productivity in China during 1961-2010.

Fengxue Gu,Yuandong Zhang,Bo Tao,Rui Guo,Changrong Yan,Mei Huang

doi:10.1002/ece3.3029

Abstract

The response of ecosystems to different magnitudes of climate warming and corresponding precipitation changes during the last few decades may provide an important reference for predicting the magnitude and trajectory of net primary productivity (NPP) in the future. In this study, a process‐based ecosystem model, Carbon Exchange between Vegetation, Soil and Atmosphere (CEVSA), was used to investigate the response of NPP to warming at both national and subregional scales during 1961–2010. The results suggest that a 1.3°C increase in temperature stimulated the positive changing trend in NPP at national scale during the past 50 years. Regardless of the magnitude of temperature increase, warming enhanced the increase in NPP; however, the positive trend of NPP decreased when warming exceeded 2°C. The largest increase in NPP was found in regions where temperature increased by 1–2°C, and this rate of increase also contributed the most to the total increase in NPP in China's terrestrial ecosystems. Decreasing precipitation depressed the positive trend in NPP that was stimulated by warming. In northern China, warming depressed the increasing trend of NPP and warming that was accompanied by decreasing precipitation led to negative changing trends in NPP in large parts of northern China, especially when warming exceeded 2°C. However, warming stimulated the increase in NPP until warming was greater than 2°C, and decreased precipitation helped to increase the NPP in southern China.

Highlights

Air temperatures have increased by as much as 0.85°C [0.65–1.06°C] from 1880 to 2012, and they are predicted to rise another 0.3–4.8°C by 2081–2100 relative to 1986–2005, based on various modeled scenarios (International Panel on Climate Change (IPCC), 2014)
Representative of many countries attending the 2015 climate conference in Paris signed an agreement to set a goal of limiting global warming to less than 2°C when compared with preindustrial era (UNFCCC, 2015)
Gao et al (2012) summarized 36 estimations from these two kinds of models in China during 1980–2000, and the results showed that net primary productivity (NPP) in China was 1.43–4.60 Pg C/year

Summary

| INTRODUCTION

Air temperatures have increased by as much as 0.85°C [0.65–1.06°C] from 1880 to 2012, and they are predicted to rise another 0.3–4.8°C by 2081–2100 relative to 1986–2005, based on various modeled scenarios (International Panel on Climate Change (IPCC), 2014). Our knowledge of how NPP might respond to different magnitudes of warming is far from clear (Niu et al, 2008; Wu et al, 2011), because this response represents an integrated effect of changes in temperature and water status on photosynthesis and respiration (Angert et al, 2005; Ciais et al, 2005; Kang, Kimball, & Runing, 2006; Sullivan et al, 2008). In addition to including the all combined simulation data such as climate change and elevated CO2 concentration, we conducted three single-factor simulations to reveal the relative effects of temperature, precipitation, and CO2 concentration on long trend of NPP.

| RESULTS AND DISCUSSION

T mean

| CONCLUSIONS